Tangerine!

Tangerine is this really cool program made by Potion Factory. It works with iTunes to make playlists of different kinds of music. For example, if I wanted a playlist of music that was slow, then the songs got gradually faster, I would tell Tangerine! just that. You just tell tangerine what pattern of songs you want, and it searches your iTunes library to make a perfect playlist! It's so awesome, I use it a lot. I definitely recommend at least taking a look at it. Just go to http://www.potionfactory.com/tangerine/ to read about it or download a free 15 day trial.